Cartons are often provided with a handle for convenient lifting and carrying. A satisfactory handle should be designed to be readily grasped, comfortable to the hand, and capable of lifting the carton without tearing. For cartons containing heavy loads, it has been common to reinforce the handle by making it of two-ply construction. For example, in fully enclosed sleeve-type cartons, the top panel often is formed by overlapping top panel flaps located at the ends of a blank. Each flap contains a handle opening arranged so that the top panel of the carton includes two spaced openings. This arrangement is sometimes referred to as a "suitcase handle" since the strap portion of the top panel between the handle openings is gripped in the manner of a suitcase handle. An example of such a suitcase handle can be found in the carton disclosed in U.S. Pat. No. 5,333,734.
U.S. Pat. No. 2,955,739 of Collura describes a handle carton in which a two-ply handle is attached to the end flaps of a carton and is positioned above the top panel of the carton. The two-ply handle is formed along the edge of the carton blank by folding and adhering one handle strip against another. The two-ply handle is then folded yet again in a "Z" fashion, causing the handle to be separated from the top panel of the carton, while still remaining attached to the end flaps.
One problem associated with cartons having handles is that uncontrolled tearing can tear across the handle itself, compromising or completely destroying the handle's ability to carry the carton. It has been known in the prior art to, in some instances, provide pre-existing cuts in a carton to control how tearing takes place. In the context of a single-ply top designed to have a punch-through hand opening, U.S. Pat. No. 4,684,059 discloses the use of control elements (including J-shaped cuts) to control the direction of tearing in the top. The J-cut portions are designed to inhibit tearing of the top panel in a direction toward the ends of the carton and to direct the tearing to the sides of the carton. In addition to J-shaped cuts, the '059 patent also discloses tear control cuts which are generally C-shaped.
At present, the common practice of the packaging industry to prevent tearing of the handle in a carton is to make the entire carton out of sufficiently heavy (thick) paperboard to provide sufficient strength for the (typically) 2-ply handle extending from one end of the carton to the other. While this provides satisfactory strength, it does so at the expense of requiring needlessly high cost paperboard for the entire carton.
Accordingly, it can be seen that a need yet remains for a carton which includes a handle which resists tearing and yet which can be made from thinner paperboard to save costs. It is to the provision of such a carton that the present invention is primarily directed.